Radio relaying system



Dec. 19, 1939. c, w, HANS L'L 2,183,562

RADI O RELAYING SYSTEM Filed April 1, i938 jWEsT TL "TL J RAD/0 2 3FREQUENCY INPUT. AMPLIFIER ourpur T l SYSTEM INVENTOR.

CLARENCE w ,f-IANSELL ATTORNEY.

Another object of the invention is to provide TL have theircharacteristic impedances sub 10 nals on the same pair of antennas, isunidirecdensers symmetrically located with respect to 15 fier whoseinput is coupled to said antennas with account the effect of each lineon the other. 20

like polarities and whose output is coupled to said Radio frequencyamplifier 4 has its input leads antennas with unlike polarities, or viceversa. 5 connected to the centers of coils 2 and 3, wound ing system tothe amplifier, and'the connections to both coils 2 and 3.

so example only, a radio relaying system embodying from the East areto'be amplified and then trans= and 3 to a radio frequency amplifier 4.The spacing of the antennas and the one-quarter 35 55 substantiallyequal toaquarter'wavelength, or an opposite phase, so that radiationcontinues to 55 Patented Dec. 19, 1939 2,183,552.

UNITED STATES; sA

2,183,562 RADIO RELAYING' SYSTEM Clarence W. Hansell, Port Jefferson, N.Y., assignor to Radio Corporation of America, a corporation of DelawareApplication April 1, 1938, Serial No. 199,420 13 Claims. (01. 250-15)This invention relates to improvements in radio odd multiple of aquarter wavelength. The referrelaying systems, and particularly to shortwave ence'numeral A indicated in the drawing repreradio relayingsystems. sents the wavelength.

One of the objects of the present invention is Both antennas A and A areconnected to the 5 to provide a radio relaying system capable ofcoupling coils 2 and 3 by transmission lines TL 6 transmitting waves inthe frequency band genand TL, respectively, which differ in length fromerally between 30 and 300 megacycles, which is each other by one-quarterof the length of the eiiicient, occupies small space, and is relativelyoperating wave, or, if desired, by an odd multiple inexpensive toconstruct. of one-quarter of the operating wave. Lines TL,

T FFECE a radio relaying system employing a pair of stantially matchedby the effective input imantennas which, although receiving signals onpedances of the antennas. Also, the coupling both antennas, isunidirectional so far as recepcoilsE, 3 and l are preferably seriestuned for tion is concerned, and, although transmitting sigthe operatingwave, each by means of two contional in a different direction, so far astransmisthe centers of the coils, and the coils are so adsion isconcerned. justed and coupled with the amplifier and the A furtherobject is to provide a radio relaying transmission lines as to providematching of the system having a pair of antennas and anamplicharacteristic impedance of the lines, taking into A feature of theinvention comprises the'three in reverse sense, and its output leads 6coupled to coils which couple the two antennas of the relaythe terminalsof central coil I, in turn coupled il'? therebetween. Let us assume thatantenna A is spaced from Other objects and features will appear fromantenna A by one-quarter wavelength, and transa reading of the followingdescription which is acmission line TL is longer than line TL byonecompanied by a drawingillustrating, by way of quarter wavelength, andthat signals arriving the principles of the invention, mitted toward theWest. It will be obvious that In the single figure of the drawing thereis the time phase relations between currents in simshown a radiorelaying system, comprising two V ilar parts of the two antennas are 90diiferent antennas A, A coupled by means of coils i, 2 in phase. Duetoithe one-quarter wavelength amplifier contains frequency selectivecircuits wavelength diiference in length of the transmisfor selectivelyamplifying a desired band of fresion lines, there is actually a one-halfwavelength quencies. difference in phase relations in the energies re-Antennas A, A are bidirectional and. of the ceived over the antennas as,applied to the coils 40 type described in Philip S. Carter United States2, 3. Because of this one-half wavelength differ-40 Patent No.1,974,387, granted September 18, 1934; ence, we can make the receivedenergy arriving each comprising a pair of diverging conductors over oneantenna either add to or oppose (i. e. adapted to be energized withopposite instantanebuck) the energy received on the other antenna. ouspolarities and to be effective in a plane The transmission line circuitconnections are through the bisector of the angle of the V. The arrangedin the present invention so that signal two antennas are symmetricallypositioned relaenergies arriving from the East and received on tive toeach other and spaced from each other both antennas A and A are suppliedto input along the bisector by a distance equal substanleads 5 in likephase from the ends of the lines tially to one-quarter of the length, oran odd mul- TL, TL terminating in the coils 2 and 3, thus tiple ofone-quarter of the length, of the operatmaking the input energies add.By reversing the 50 ing wave. Putting it another way, the spacing senseof coupling of the coils 2 and 3, however, between antennas A and Ameasured along the in the manner shown in the drawing, the amplicenterline of their bidirectional beams, or in the fied output energy fromleads 6 is supplied to the desired direction of maximum radiation-ismade same ends of the transmission lines in unlike or ward the West. Thetwo arrows along coils 2 and 3 indicate that the relative phases of theoutput currents are reversed to produce radiation of signals from eastto west. In other words, transmission lines TL and TL are coupled to theinput of the amplifier 4 in like polarity in order to obtain addition ofinput energies received over both antennas and arriving from onedirection (east), while these same transmission lines TL, TL are coupledto the output of the amplifier 4 in unlike polarity in order to have theamplified signals radiated from both antennas in the opposite direction(west). We thus have a unidirectional repeater or radio relaying system.

If signals from a distant transmitter pass the antennas in the wrongdirection, from West to east, then the two transmission lines will bringcurrents to the amplifier input terminals which are of opposite phaseand therefore tend to balance out so that they are amplified only feeblyif at all. Most of the energy picked up returns to the antennas and isreradiated, or is absorbed in the amplifier output circuits withoutbeing amplified.

It will be apparent that the directions of reception and transmission ofthe whole relaying system can be reversed merely by reversing theconnections to one transmission line, either at the antenna terminals orat the place where the lines are joined together, in which case theinput of the amplifier will be coupled to the ends of the transmissionlines in unlike polarity while the output of the amplifier will becoupled to the same ends of the transmission lines in like polarity.

Although the spacing between antennas has been mentioned as beingone-quarter wavelength, it should be understood that this spacing may beany odd multiple thereof, and that the transmission lines may alsodifier in length by any odd multiple of one-quarter wavelength. However,the spacing between antennas and the difference between lengths oftransmission lines should not be excessive in magnitude, particularly ifa wide percentage band width of current frequencies is to be relayed.

Due to the mutual coupling between the two antennas A and A,particularly if they are close together, they will ordinarily notdeliver exactly equal energies at the terminals of the transmissionlines, in the case of reception, nor will they require exactly equalenergies in the case of transmission. This introduces some imperfectionin the unidirectional receiving and transmitting characteristics of thesystem. It also tends to introduce coupling from the output circuit ofthe amplifier back into the input. This feedback coupling tends to causeoscillation of the radio frequency amplifier if the feed-back power issufficiently great. Even though oscillation may take place, the systemis capable of functioning satisfactorily for the relay of frequencymodulated Waves, so long as the received energy is capable ofcontrolling the frequency of oscillation. In practice I contemplateadjusting the couplings from coil 1 to each half of each coil 2 and 3,and adjusting the taps of line 5 onto coils 2 and 3 until minimumfeed-back from output to input of the amplifier, in the desiredfrequency band, is obtained. In this case there may be some undesiredback radiation or reception, but this can be tolerated. Of course it isdesirable to design the antennas for as little mutual coupling aspossible consistent with other desired characteristics.

The coupling circuit transformers may be tuned to reduce the effects ofleakage reactance. Also, the circuits may be made of sections of lowimpedance line, preferably about a half Wave long each, use being madeof the principles described and illustrated in my copending applicationSerial No. 199,421, filed April 1, 1938, which teaches how halfwavelength low impedance lines can be employed for the same generalpurpose.

The amplifier 4 need not have a linear response characteristic if it isused to relay a frequency or phase modulated signal and, in fact, inthis case some amplitude limiting in the amplifier is desirable.

The term odd multiple of a quarter wavelength used in the appendedclaims is intended to include any odd multiple, including unity.

What is claimed is:

l. A radio relaying system having a pair of antennas spaced apart fromone another in the direction of transmission by an odd multiple ofone-quarter the length of the operating wave, an amplifier, andindividual transmission lines extending from said antennas toward saidamplifier, said lines differing from each other by an odd multiple ofone-quarter the length of the operating wave, and means for coupling theinput of said amplifier to said transmission lines in like polarity andthe output of said amplifier to said lines in unlike polarity.

2. A radio relaying system having a pair of antennas spaced apart fromone another in the direction of transmission by an odd multiple ofone-quarter the length of the operating Wave, an amplifier, andindividual transmission lines extending from said antennas toward saidamplifier, said lines difiering from each other by an odd multiple ofone-quarter the length of the operating wave, and means for coupling theoutput of said amplifier to said transmission lines in like polarity andthe input of said amplifier to said lines in unlike polarity.

3. A radio relay system having two antennas spaced apart in thedirection of transmission by an odd multiple of one-quarter the lengthof the operating wave, an amplifier having an input circuit and anoutput circuit, individual transmission lines extending from saidantennas toward said amplifier, said lines differing from each other byan odd multiple of one-quarter the length of the operating wave, andmeans for coupling one of said circuits of said amplifier to saidtransmission lines in like polarity, and the other circuit to saidtransmission lines in unlike polarity.

4. A radio relaying system for receiving signal energy from onedirection and for transmitting amplified signal energy in a differentdirection, comprising a pair of bidirectional antennas spaced apart inthe direction of transmission by an odd multiple of one-quarter thelength of the operating wave, an amplifier having an input circuit andan output circuit, individual transmission lines extending from saidantennas toward said amplifier, said lines differing from each other byan odd multiple of one-quarter the length of the operating wave, andmeans for coupling one of said circuits of said amplifier to saidtransmission lines in like polarity, and the other circuit to saidtransmission lines in unlike polarity.

5. A radio relaying system for receiving signal energy from onedirection and for transmitting amplified signal energy in a differentdirection, comprising a pair of bidirectional V antennas diverging inthe same direction and spaced apart from each other in thedesireddirection of maximum radiation by an odd multiple of onequarter of thelength of the working wave, an amplifier having an input circuit and anoutput circuit, individual two conductor transmission lines extendngfrom said antennas toward said amplifier, said linesdiifering from eachother by an odd multiple of one-quarter the length of the operatingwave, and means for coupling one of said circuits of said amplifier tosaid transmission lines in like polarity, and the other circuit to saidtransmission lines in unlike polarity.

6. A system in accordance with claim 3, characteriz'ed in this that saidmeans comprises three coils, two of which are coupled in reverse sensewith respect to each other and coupled to the third coil, connectionsfrom points intermediate the ends of'said two coils to said inputcircuit, connections from the terminals of said third coil to saidoutput circuit, and connections from the conductors of one transmissionline to correspondingly located terminals of said two coils, andconnections from the conductors of the other transmission line to theother terminals of said two coils.

7. In an antenna system having a pair of antennas and an amplifiercoupled between said antennas, the method of operation which includesreceiving signals from one direction on both of said antennas, andimpressing said signals in like phase upon the input of said amplifier,and applying output energy. from said amplifier upon both said antennasin such phase as to produce predominant radiation in a directionsubstantially opposite to that of the received signals.

8. In an antenna system having a pair of antennas spaced from each otherand both coupled to electron discharge device apparatus, the method ofoperation which includes applying the signal waves received on both saidantennas from one direction to said electron discharge device apparatusin substantially the same phase,

and applying the signal waves received on both said antennas fromanother direction to said apparatus in substantially opposite phase.

9. In an antenna system having a pair of antennas spaced from each otherand both coupled to electron discharge device apparatus, the method ofoperation which includes applying the signal waves received on both saidantennas from one direction to said electron discharge device apparatusin substantially the same phase, applying the signal waves received onboth said antennas from another direction to said apparatus insubstantially opposite phase, and radiating energy from both saidantennas predominantly toward said other direction.

10. In an antenna system having a pair of antennas spaced from eachother and both coupled to an amplifier, the method of operation whichincludes applying the signal waves received on both said antennas fromone direction to said amplifier in substantially the same phase,limiting the amplitude of the signal waves passing through saidamplifier, and applying the amplified signal waves to said antennas insuch manner as to produce radiation therefrom pre dominantly in adirection away from that of the received Waves.

11. A radio relaying station having a pair of antennas spaced apart fromone another, an amplifier, feederlines from said antennas extending tosaid amplifier, a circuit intermediate said feeder lines and saidamplifier for coupling the input and output of said amplifier to saidpair of antennas, said antennas being so spaced and said feeder lineshaving such lengths and being so connected to said intermediate circuitthat signals received on both of said antennas from one direction areapplied to the input of said amplifier in like phase and signalsreceived on both of said antennas from an opposite direction are appliedto the input of said amplifier in substantially opposite phase.

12. A radio relaying station having a pair of antennas spaced apart fromone another, an amplifier, feeder lines from said antennas extending tosaid amplifier, a circuit intermediate said feeder lines and saidamplifier for coupling the input and output of said amplifier to saidpair of antennas, said antennas being so spaced and-said feeder lineshaving such lengths and being so connected to said intermediate circuitthat signals received on both of said antennas from one direction areapplied to the input. of said amplifier in like phase and signalsreceived on both of said antennas from an opposite direction are appliedto the input of said amplifier in substantially opposite phase, saidintermediate circuit comprising three coils, two of which are arrangedin reverse sense to each other and coupled to the third coil, said twocoils being connected to said feeder lines and the input of saidamplifier while said third coil is connected to the output of saidamplifier.

13. A radio relaying station comprising a pair of parallel antennasspaced apart from one another by substantially an odd multiple ofonequarter the length of the operating wave, each ends of the arms ofeach antenna to said amplifier, said feeders differing in length fromeach other by substantially an odd multiple of onequarter the length ofthe operating wave, and circuit means intermediate the input and outputof said amplifier and said feeders, said circuit means comprising threecoils, two of which are arranged in reverse sense with respect to eachother and coupled to the third coil located intermediate said first twocoils, connections from points intermediate the ends of said first twocoils to the input of said amplifier, connections from the ends of saidfirst two coils to said feeders, and connections from the ends of saidthird coil to the output of said amplifier, whereby signals received onsaid antennas from one direction are applied in like phase to the inputof said amplifier, while signals received on said antennas from asubstantially opposite direction are applied in opposite phase to theinput of

